person = {
    'firstName': 'shen',
    'lastName': 'albert',
    'age': '20',
    'city': 'suzhou'
}
print(person['city'])

heigh = person.get('heigh', 'no heigh')
print(heigh)

person['heigh'] = '170'
heigh = person.get('heigh', 'no heigh')
print(heigh)

del person['heigh']
print(person)
